Two wire clip-type terminal and tool for operating same

ABSTRACT

A clip terminal is made from resilient strip stock. It has two notches at its upper end which connect with narrow slots which separate the body portion into a center arm and two end arms. The width of each end arm is less than the width of the center arm so that the stiffness of the center arm is more than twice the stiffness of either end arm. The tool for inserting a wire in either slot has a recess which receives all three arms. The insertion of the wire deflects one end arm, but the side of the recess limits the deflection. The surfaces of the recess each have a groove to receive a boss formed on the center arm so that the deflection of either end arm will be limited independently of the other end arm.

United States Patent [72] Inventor William S. Sedlacek Chicago, Ill.[2]] Appl. No. 827,013 [22] Filed May 22, 1969 [45] Patented Sept. 14,1971 [73] Assignee Reliable Electric Company Franklin Park, Ill.

[54] TWO WIRE CLIP-TYPE TERMINAL AND TOOL FOR OPERATING SAME ll Claims,5 Drawing Figs.

[52] US. Cl 339/97 P [5|] lnt.Cl l-l0lr9/08 [50] Field of Search 339/95,97-99 [56] References Cited UNITED STATES PATENTS 2,694,] 89 ll/l954Wirsching 339/97 3,027,536 3/l962 Pasternak 339/97 3.167375 1/1965Sarazen 339/99 3,394 454 7/l968 Logan 29/629 Primary Examiner-Ian A.Calvert Assistant Examiner-Joseph H. McGlynn Attorney-Olson, Trexler,Wolters & Bushnell ABSTRACT: A clip terminal is made from resilientstrip stock. it has two notches at its upper end which connect withnarrow slots which separate the body portion into a center arm and twoend arms. The width of each end arm is less than the width of the centerarm so that the stiffness of the center arm is more than twice thestiffness of either end arm. The tool for inserting a wire in eitherslot has a'recess which receives all three arms. The insertion of thewire deflects one end arm, but the side of the recess limits thedeflection. The surfaces of the recess each have a groove to receive aboss formed on the center arm so that the deflection of either end armwillbe limited independently of the other end arm.

PATENIEDsmMsn 3.605.071

INVENTOR WILLIAM S. SEDLAC EK ATT'YS.

BY m g gw TWO WIRE CLIP-TYPE TERMINAL AND TOOL FOR OPERATING SAME Thisinvention relates to a clip-type terminal which will receive twoinsulated wires. The clip-type terminal is a flat piece of metal havingintegrally formed resilient arms providing one or more conductor-receiving slots. The insulated wire is forced into a slot which is of awidth considerably less that the diameter of the conductor, that is ofthe copper. The process of inserting the conductor into this slotresults in a penetration of the insulation so that electrical contact isobtained between the slot edges and the conductor.

In previous devices of this type which are adapted'to receive more thanone conductor, there is a separate pair of arms for each conductor, allof the arm pairs being formed from a single strip of metal.

In the use of multiwire clip terminals, the most common demand is for atwo wire clip terminal. Considerable space would be saved if the twowire clip terminal could be made with a total of three arms, providingtwo slots, the middle arm being common to both slots.

The nature of these clip terminals is such that considerable force isrequired to insert a wire into its slot, with the result that a specialtool has been provided having end surfaces which engage the insulatedwire at a point immediately adjacent the side surface of the arms, sothat the wire can be forced into the slot, thus spreading the arms. Inthe single wire clip terminal, both arms flex an equal amount.

The characteristic of a clip-type terminal, whether of the insulationcrushing type or insulation stripping type, is that the contact forcedeveloped by the clip arms must be sufficient to effect the desiredcrushing or stripping of the insulation, but at the same time, not sogreat as to pinch off the conductor or to materially weaken the same bynicking.

It is also desirable to design a clip that will accommodate severalsizes of conductor; with the larger sizes there is a greater deflectionof the arms, and therefore a greater force is exerted on the conductor.This in itself is not particularly objectionable since the largerdiameter conductors are better able to resist the pinching off effect,but there are other factors involved which tend to limit theadaptability or accommodation of the clip to not more than two or threeor four even numbered adjacent wire sizes, at least in the range of from20-gauge down to 28-gauge.

In a two wire clip terminal having a common center arm, both of the endarms react against the insertion of a wire. Thus, the insertion of thesecond wire would ordinarily require considerably more force than theinsertion of the first wire due to the fact that one end arm is alreadystressed to an extent corresponding to its deformation. Therefore, theforce ordinarily exerted by the clip arms on the second wire might be sogreat as to pinch off the conductor, at least with respect to the largerwire sizes, or even to prevent entry into the slot. In other words, therange of forces encountered would be greater than those encountered inthe design for a single clip terminal.

According to my invention, 1 have found that it is possible to develop acontrolled stripping or crushing force even though there is a commoncenter arm. More specifically, l provide a much stiffer center arm, andthen design the end arms so that each develops the desired force atabout twice the deflection that would occur if both arms were of equalstiffness. Then, when the second wire is inserted, there will becomparatively little movement of the center arm and thus little furtherdeflection of the remote end arm.

In the drawings: I

FIG. I is an elevation of a preferred embodiment of my invention;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a side view of the tool, partially broken away;

FIG. 4 is a plan view along line 4-4 of FIG. 3; and

FIG. 5 is an end view of FIG. 3. In FIG. 1, the clip comprises a flatbody portion of resilient metal having two notches 11 at its upper partand two elongate apertures 12 at its lower part. A slot 13 connects eachnotch with each aperture, thus providing three arms 14, 15 and 16. I

The slots 13 are formed by a shearing or slitting operation after whichportions are upset or coined at 17 which forces the end arms 14 and 16away form the middle are 15 to an extent such that the width of eachslot immediately adjacent the portion.15 is about 0.002 inches, and thewidth of the upper end I of each slot is 0.009 to 0.012 inches. Thisslitting operation makes the edges of the slots 13 sharp and square.

The bottom of each notch 11 is preferably rounded providing oppositelydisposed sharp corner edges 19 in the manner pointed out in my copendingapplication, Ser. No. 807,336 filed Mar. 14, 1969. However, a V-shapedslot entry, instead of a rounded entry, may be provided, as pointed outin U.S. Pat. Nos. 3,112,147 and 3,234,498, dated Nov. 26, 1963 and Feb.8, 1966, respectively.

The upper notch edges 20 may be either parallel or downwardlyconverging. A lateral extension 21 on the middle arm 15 cooperates withthe rounded top of each of the outer arms 14 and 16 to facilitate entryof an insulated wire where the total wire diameter exceeds the notchwidth.

The lower end of the body portion 10 is no part of my invention. Forinstance, it may include a terminal end 23 to permit solderedconnections or wire wrapped connections, and a tab 24 for securing theclip to a holder, as by wedging. In the alternative, a plurality of twoclip terminals could have a common base portion, as is done with thesingle clip terminals shown in said U.S. Pat.No. 3,112,147.

The body portion 10 is preferably formed from spring tempered phosphorbronze strip alloy No. A having a thickness of 0.044 inches. After thestamping, slitting and upsetting opera tions are performed, the clip isheat treated at 450 F. for 1 hour for stress relief. Then the clip iselectroplated with tin or other suitable metals.

In the example illustrated, which accommodates three wire sizes 22gauge, 24 gauge and 26 gauge, the end arm length between the corner edge19 and the bottom of the aperture 12 is 0.670 inches, and the arm widthat these two points is 0.070 and 0.097 inches respectively, ascontrasted with arm widths of 0.082 and 0.107 inches for the single clipterminal shown in my above mentioned copending application. Thisreduction in width represents a 40 percent reduction in stiffness. Atthe same time, the width of the center arm at a point between the twoapertures is substantially 0.114 inches, thus making the center armabout three times as stiff as the end arms, insofar as this section isconcerned. Actually both the center and end arms are of varying width sothat the stiffness ratios are approximate only.

In the round entry type of clip shown, the deflection of the end armwith 26 gauge wire is about 0.004 to 0.007 inches, whereas with 22 gaugewire it is from 0.013 to 0.016 inches, or a little less if thedeflection of the center arm is taken into account, these deflectionsbeing well within the elastic limit of the arms.

As an aid to the insertion of the wire, a tool 27 is provided as shownin FIGS. 3 to 5, the tool providing a recess 28 to accommodate the upperends of the arms 14, 15- and 16, the outer edges 29 of the arms beingsubstantially parallel in this region. The width of the recess 28 issuch that it will accommodate a certain amount of deflection of each endarm 14, 16.

In the case of the round slot entry shown, a deflection of up to 0.016inches is permitted, thus accommodating all wire sizes from 22 gaugedown to 26 gauge, but limiting the extent of the flexure so that it willnot exceed the elastic limit of the clip material.

In the case of the V-shaped slot entry shown in aforesaid U.S. Pats.Nos. 3,112,147 and 3,234,498, the amount of arm deflection is somewhatmore restricted because the reaction of the tool on the arm edges 29 isrequired in order to develop sufficient force to crush the insulationand at the same time to assure integrity of the contact between the slotedge and the conductor. For instance, with the V-shaped slot entry, onlya 0.006 inch deflection would be permitted in a tool accommodating a 24gauge wire.

With the larger wire sizes, situations may occur in which the deflectionof an arm will exceed the elastic limit of the clip material. This isparticularly true if the insulation coating is thicker than standard,and the situation will also arise where an attempt is made to insert awire of a size greater than the maximum size from which the clipterminal is rated. Therefore, the tool is intended to perform adeflection limiting function as above described.

However, when a tool is designed for use with a two wire clip terminalhaving a common center arm, the deflection permitted for one arm wouldadd to the deflection permitted for the other, so that the maximumdeflection for the first wire to be inserted would be twice thepermissible limit.

According to my invention, I provide locating means between the centerarm and the tool 27 so that the maximum deflection for each end arm willnot be cumulative. This locating means thus provides a point ofreference by means of which the deflection of either end arm is limitedwith respect to the center arm, rather that with respect to the otherend arm.

The locating means referred to comprises a circular locating boss 30formed at the upper end of the center arm as shown in FIGS. 1 and 2. Theboss 30 is located along the centerline of the symmetrically designedclip, so that it is half way between the parallel arm edges 29. Surfaces31 and 32 of the recess 28 are each provided with a slot 33 and 34 toaccommodate the boss 30 in either forwardly or rearwardly facingorientation. The boss diameter and the slot width are formed tosufficiently close tolerances as to avoid appreciable sideplay whilestill permitting free sliding movement. Thus, when inserting the firstwire, which is positioned for example in the notch 11 between the centerarm 15 and the end arm 16, the tool 27 is placed over the upper ends ofthe three arms 14, 15 and 16 and pushed downwardly until the wireinsulation is urged against the sharp corner edges 19. The end surfaces35 of the tool apply pressure to the wire immediately adjacent the sidesurfaces of the clip so that the amount of force required to cam thesharp corner edges 19 apart can be transmitted to the conductor of theinsulated wire. The outer side walls of the recess 28 are chamfered asat 36 to facilitate initail application.

Irrespective of the diameter of either the insulated wire as a whole orof the metallic conductor portion, the deflection of the arm 16 wheninserting the first wire is limited, and the same applies with respectto the insertion of the second wire. Furthermore, my invention permitsthe use of two wires of differing size, one in each slot 13.

As shown in FIGS. 3 to 5, the tool is preferably made from two strips oftool steel which are secured to each other by pins 37.

In the example shown, the elongate apertures 12 define for the lowerpart of the center arm 15 a section 38 of substantially uniform width,and having a length substantially in excess of the width, preferablyfrom 2% to 3 times the width dimension. Being located in the lower endof the arm, the width of the section 38 substantially controls thestiffness of the arm as a whole. Thus, the effective width of the arm issubstantially equal to the width of this section 38 insofar as stiffnessis concerned.

The stiffness of the end arm should be such that the forces developed bya deflection thereof equal to the difference between the diameter of theconductor portion of the largest wire size for which the clip is rated,and the slot width, will be less than the elastic limit of the resilientmaterial of which the arm is made. In the example shown, the effectivewidth of the end arm is from 0.075 to 0.080 inches, making the centerarm from three to four times stitTer than an end arm. Where the terminalis rated for one wire size only, a stiffness ratio of two to one wouldbe sufficient. The foregoing corresponds to an effective width ratio ofcenter arm to end arm of from 1.5 to 1.6 for the example given, and of1.25 for the single wire size rating.

Although the present invention is suitable with either the insulationcrushing or insulation stripping type of clip terminal,

the latter type which is characterized by a round slot entry as pointedout in my aforesaid eopending application, Ser. No. 807,336, isparticularly suitable for use in the present invention because thedesired stripping force can be determined more definitely that the forcerequired for crushing the insulation.

The operation of the stripping type of clip terminal is pointed out indetail in the aforesaid eopending application, and the disclosure ofsame is incorporated herein by reference, insofar as consistent with theteaching of the present application.

The width of the lower portion of the notch 11 is substantially 0.040inches, and the notch cooperates with the overall diameter of theinsulated wire to regulate the width of the slot 13 to the end that agiven clip can be rated to accommodate a range of sizes of insulatedwire, as pointed out in the aforesaid eopending application. The wiresize ratings referred to herein apply to the diameter of the conductorportion of the insulated wire, the over all diameter being from two tothree times the conductor diameter.

lclaim:

l. A two wire clip terminal comprising an elongate flat body formed fromflat resilient metal and having two notches at its upper part, a baseportion at its lower part, and a slot communicating with the lower endof each notch, said slots providing a center arm and two end armsextending in the same direction from a common base, the outer ends ofsaid arms being free so as to provide three cantilever beams arrangedside by side, the effective width of each end arm being less that theeffective width of said center arm to render each end arm more compliantthan said center arm when a wire is inserted into one of said slots.

2. A two wire clip terminal as claimed in claim 1 which is rated for thediameter of the conductor portion of an insulated wire, and in which theeffective width of each end arm is such that the end arm will beresilient when deflected to an extent equal to the difference betweensaid rated diameter and the slot width, the stiffness of said center armbeing in excess of two times the stiffness of either end arm.

3. A tow wire clip terminal as claimed in claim 1 which is rated for arange of wire sizes, each representing the diameter of the conductorportion of an insulated wire, and in which the effective width of eachend arm is such that the end arm will be resilient when deflected to anextent equal to the difference between the conductor diameter of thelargest wire size rating and the slot width, the stiffness of saidcenter arm being in excess of substantially three times the stiffness ofeither end arm.

4. A two wire clip terminal as claimed in claim 1 in which the effectivewidth of said end arm is less than 70 percent of the effective width ofsaid center arm.

5. A two wire clip terminal as claimed in claim 1 which is rated for thediameter of the conductor portion of an insulated wire, and in which thebottom of each notch is rounded and has arcuate straight side edgeswhich intersect the edges of said slot to provide substantially sharpcorner edges, the width of each said slot at said corner edges being nogreater than said rated diameter.

6. A two wire clip terminal as claimed in claim 1 which includes anelongate aperture spaced below each notch, said slot extending betweenthe bottom of each notch and the upper end of said aperture.

7. A two wire clip terminal as claimed in claim 6 in which said elongateapertures define for said center arm, a section having a substantiallyuniform width, said section being of a length substantially greater thansaid width so that the effective stiffness of said center arm isdetermined primarily by the width of said section.

8. A two wire clip terminal as claimed in claim 6 in which the edges ofeach said slot at a point adjacent to its associated aperture are upsetto prestress said end arms and provide a slot width of substantially0.010 to 0.012 inches at a point adjacent said notch.

9. A combination two wire clipterminal and tool for inserting aninsulated wire therein comprising an elongate flat body portion formedfrom flat resilient metal and having two notches at its upper end, anelongate aperture spaced below each notch, and a slot extending betweenthe bottom of each notch and the upper end of said aperture providing acenter arm and two end arms, the effective width of each end arm beingless than the effective width of said center arm to render said end armmore compliant than said center arm to render said end arm morecompliant than said center arm when a wire is inserted into one of saidslots, a tool having a recess for receiving the upper end of said clipterminal and having end surfaces engaging an insulated wire located insaid notch to facilitate the insertion of said wire into said slot, thewidth of said recess being greater than the width of the upper portionof said clip by a predetermined distance, and locating means on saidcenter arm and said tool for centering said tool with respect to saidclip terminal so that the deflection of each arm will be limited tosubstantially one-half of the aforesaid predetermined distance.

10. A combination two wire clip terminal and tool as claimed in claim 9in which said locating means comprises a boss extending fromone surfaceof said center arm, and a groove in a wall of said recess for receivingsaid boss in sliding relationship.

11. A two wire clip terminal comprising an elongate flat body portionformed from flat resilient metal and having two notches at its upperend, a slot communicating with the lower end of each notch, said slotsproviding a center arm and two end arms, the effective width of each endarm being less than the effective width of each said center arm torender each end arm more compliant than said center arm when a wire isinserted into one of said slots, and a locating boss projecting from onesurface of said center arm providing a point of reference for limitingthe deflection of one end arm with respect to said center arm.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENTNO.: 3,605,071 DATED September 14, 1971 INVENTOR(S) 1 William S.Sedlacek It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 29, change "that" to than Column 4, line 42 change "tow"to two Column 4, line 56, delete "straight side";

same line before "edges" (second occurrence) insert straight side Signedand Scaled this Fifteenth Day OI May I979 [SEAL] Amm DONALD W. BANNERRUTH C. MASON Arresting Omen Commissioner of Patent: and Trademarks

1. A two wire clip terminal comprising an elongate flat body formed fromflat resilient metal and having two notches at its upper part, a baseportion at its lower part, and a slot communicating with the lower endof each notch, said slots providing a center arm and two end armsextending in the same direction from a common base, the outer ends ofsaid arms being free so as to provide three cantilever beams arrangedside by side, the effective width of each end arm being less that theeffective width of said center arm to render each end arm more compliantthan said center arm when a wire is inserted into one of said slots. 2.A two wire clip terminal as claimed in claim 1 which is rated for thediameter of the conductor portion of an Insulated wire, and in which theeffective width of each end arm is such that the end arm will beresilient when deflected to an extent equal to the difference betweensaid rated diameter and the slot width, the stiffness of said center armbeing in excess of two times the stiffness of either end arm.
 3. A towwire clip terminal as claimed in claim 1 which is rated for a range ofwire sizes, each representing the diameter of the conductor portion ofan insulated wire, and in which the effective width of each end arm issuch that the end arm will be resilient when deflected to an extentequal to the difference between the conductor diameter of the largestwire size rating and the slot width, the stiffness of said center armbeing in excess of substantially three times the stiffness of either endarm.
 4. A two wire clip terminal as claimed in claim 1 in which theeffective width of said end arm is less than 70 percent of the effectivewidth of said center arm.
 5. A two wire clip terminal as claimed inclaim 1 which is rated for the diameter of the conductor portion of aninsulated wire, and in which the bottom of each notch is rounded and hasarcuate straight side edges which intersect the edges of said slot toprovide substantially 90* sharp corner edges, the width of each saidslot at said corner edges being no greater than said rated diameter. 6.A two wire clip terminal as claimed in claim 1 which includes anelongate aperture spaced below each notch, said slot extending betweenthe bottom of each notch and the upper end of said aperture.
 7. A twowire clip terminal as claimed in claim 6 in which said elongateapertures define for said center arm, a section having a substantiallyuniform width, said section being of a length substantially greater thansaid width so that the effective stiffness of said center arm isdetermined primarily by the width of said section.
 8. A two wire clipterminal as claimed in claim 6 in which the edges of each said slot at apoint adjacent to its associated aperture are upset to prestress saidend arms and provide a slot width of substantially 0.010 to 0.012 inchesat a point adjacent said notch.
 9. A combination two wire clip terminaland tool for inserting an insulated wire therein comprising an elongateflat body portion formed from flat resilient metal and having twonotches at its upper end, an elongate aperture spaced below each notch,and a slot extending between the bottom of each notch and the upper endof said aperture providing a center arm and two end arms, the effectivewidth of each end arm being less than the effective width of said centerarm to render said end arm more compliant than said center arm to rendersaid end arm more compliant than said center arm when a wire is insertedinto one of said slots, a tool having a recess for receiving the upperend of said clip terminal and having end surfaces engaging an insulatedwire located in said notch to facilitate the insertion of said wire intosaid slot, the width of said recess being greater than the width of theupper portion of said clip by a predetermined distance, and locatingmeans on said center arm and said tool for centering said tool withrespect to said clip terminal so that the deflection of each arm will belimited to substantially one-half of the aforesaid predetermineddistance.
 10. A combination two wire clip terminal and tool as claimedin claim 9 in which said locating means comprises a boss extending fromone surface of said center arm, and a groove in a wall of said recessfor receiving said boss in sliding relationship.
 11. A two wire clipterminal comprising an elongate flat body portion formed from flatresilient metal and having two notches at its upper end, a slotcommunicating with the lower end of each notch, said slots providing acenter arm and two end arms, the effective width of each end arm beingless than the effective width of each said center arm to render each endarm more compliAnt than said center arm when a wire is inserted into oneof said slots, and a locating boss projecting from one surface of saidcenter arm providing a point of reference for limiting the deflection ofone end arm with respect to said center arm.